Are these pee bricks the future of construction?

If you did a Top Ten of issues facing the world, 'waste recycling' and 'shelter' would definitely be somewhere on that list. Around the globe, people need safe, sturdy homes. And the more ways that we can upcycle (discover things that we can make from) our waste, the better.

So when researchers at the University of Cape Town in South Africa tell us that they've found a way to make bricks out of human urine, our first response is "sounds amazing!"

Okay, actually that was our second response. Our first thought was "Pee bricks? How on earth did you think to do that?"

Liquid gold

Because let's be honest, here. When you think of your own urine, building materials is not exactly the first thing that comes to mind. (We're pretty sure that it would never come to mind, frankly.) So what makes this fluid liquid gold for builders?

World-first: Bio-bricks grown from human urine have been unveiled @UCT_news this week, signalling an innovative paradigm shift in waste recovery. Full story: https://t.co/iSjI9mn2c8 pic.twitter.com/Ogjpkx1v2l

— UCT Research (@UCT_Research) October 24, 2018

Turns out that the secret to these bricks—or bio-bricks, as is the official name—is that urine contains a number of elements—nitrogen, potassium, and phosphorus—that make for a very strong substance. (When mixed with the right ingredients, of course.)

Basically the urine is mixed with sand and bacteria. Over time, a complex chemical reaction occurs in the mixture that causes it to solidify into whatever shape you choose. In this case, it's a brick.

Who needs a bathroom brick?

(Robyn Walker/University of Cape Town)

Basically, the process 'grows' a brick. This mind-blowing method is very environmentally-friendly, and not just because it upcycles our pee. It also requires no heat at all. Regular bricks must be fired in an oven called a kiln. Kilns reach a scorching 1,400°C (2,552°F) and produce a whole lot of carbon dioxide (a.k.a. that thing that we need less of in the atmosphere right now).

Still, there has to be some kind of drawback to a bio-brick made of urine. It's true that a single brick takes around 25 to 30 litres (6.5 to 8 gallons) of pee to grow. That's a lot, but if we really focused how we collected human urine for production, it's not as though there aren't millions upon millions of people who could help with this.

And yes, they do take a little while to stop stinking. The smell of ammonia lingers in the pee bricks for about 48 hours after they are made.

Still, when you balance that against the positive, it's hard to see a reason not to get behind the bio-brick.